Time is running out for the most important environmental negotiations in history - the UN talks about what rich countries should do about about man-made climate change caused by our use of fossil fuels.

The most important player is the United States, which produces the most emissions per capita and in total. It has yet to declare its hand. But American industry, and particularly its giant oil and energy multinationals, are lobbying skillfully against the significant cuts needed to make a start on tackling the threat.

The Washington-based Global Climate Coalition only has a staff of four but represents tens of thousands of small and medium-sized US businesses, as well as oil and utility giants. ``We're not large, we're just, I guess, pretty effective," a spokesman told The Independent.

Two years ago the developed nations, including Russia and the former Warsaw pact nations, promised to come up with firm, legally binding commitments to cut their emissions of greenhouse gases from 2000 onwards. They also promised to reach an agreement on precisely what this commitment should be at a conference of climate treaty nations in Kyoto, Japan in December.

The different factions among the rich states are still poles apart, with three weeks of negotiations booked before Kyoto.

At one extreme is Australia, which refuses to contemplate any cuts in its output of carbon dioxide, the most important of the man-made global warming pollutants. Australia is highly dependent on using and exporting coal, the most polluting of the fossil fuels. It has major metal smelting industries which belch out the gas.

At the other extreme is the European Union, which claims world leadership on the issue by making a firm commitment to cut its emissions by 10 per cent between 2000 and 2010. Europe says it is willing to deliver a 15 per cent cut, provided the other industrialised countries agree, though as yet it has no strategy to achieve this.

The other negotiators find Europe's virtuous position disturbing. Some of the less wealthy, still industrialising, EU states are allowed large increases in emissions over this period - 40 per cent in the case of Portugal. The idea is that this will be offset by big cuts among wealthier member states, so the Union as a whole will hit the 10 per cent target.

Under the last government, Britain agreed to sign up to a 10 per cent cut in emissions. The new government has come into office with a manifesto commitment to make a 20 per cent cut, but admits it has yet to devise policies needed to do so.

The environment minister, Michael Meacher, indicated this week that unless the rest of Europe was willing to work towards tougher targets, this 20 per cent commitment would not be forthcoming, because meeting it would involve "real pain for business and consumers".

Japan, another key player, has not yet pledged any cuts, nor has the US. The White House says it is difficult to make commitments, with powerful energy industry lobbyists and a conservative Congress that sees emission limits as a foreign threat to the gas-guzzling American economy.

The US is, however, insisting rich countries should be allowed to make some of their contribution by helping developing nations control their fast-rising emissions.

This would mean demonstrating that instead of making a cut at home it had enabled China, for example, to slow the rate at which its emissions are rising by an equivalent amount. The EU has real doubts about the value of this approach.

Demanding much deeper cuts than any industrialised nation will contemplate is an alliance of small island states which are frightened that much of their habitable land will disappear as sea levels rise.

Meanwhile, Opec nations, such as Saudi Arabia, are suggesting that if the world cuts its oil use, they must be compensated for a loss in exports.

The main idea behind the Kyoto deal is that the rich nations would lead the way in attacking the threat of devastating shifts in climate, because they have produced most of the pollution to date and still do. Only then can the developing countries, whose share of emissions is rising, be expected to follow.

The multinational oil companies, mostly US-based, no longer speak with one voice. The European ones, BP and, to a lesser extent, Shell, say it is time for countries to take the threat seriously, though they do not suggest selling less oil.

Dr Bob Watson, the World Bank's chief scientist and a former pupil at an Essex grammar school, was until recently science adviser to the White House. He guesses that President Bill Clinton will offer a 5 per cent cut between 2000 and 2010.

The leaders of the rich countries, including Britain, will discuss the issue at the G7 summit in Denver in a fortnight. It will dominate the five-year follow-up to the Rio earth summit in New York held afterwards.

Chris Rose, deputy chief executive of Greenpeace UK, said: "It's 50-50 whether Kyoto ends disastrously or fairly well." He said it was extremely important to set a target for cuts in 2005, because that would be within today's politicians' terms of office.

If the chance is missed to make a start on cutting emissions in Japan this year, then the cumbersome pace of climate diplomacy dictates that it will be years before fresh attempts could be made.

John Schlaes, executive director and founder of the Global Climate Coalition, said:"These things can't be determined on the basis of emotion ... countries are going to have to decide, ultimately, what is in their own best interests."